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Pseudoxanthoma elasticum (PXE) is a rare disease. Its incidence has been estimated at 1/25,000-50,000. However, the true incidence is unknown, as it is likely that some patients are so mildly involved that they escape diagnosis and some have atypical presentations.

One of the body systems affected by pseudoxanthoma elasticum (PXE) is the eyes. It is thought that most affected individuals develop angioid streaks associated with calcification of elastin-rich tissues in the eye.

Angioid streaks do not necessarily affect vision, however further changes to the eye may cause loss in central vision. A person with PXE rarely, if ever, becomes totally blind, however they may lose central vision to the extent that they become legally blind, and able to see only through peripheral vision.

Angioid streaks are not visible to the patient, and can be observed only during ophthalmologic examination. They appear as broad, irregular lines of red, brown or gray, which radiate from the area around the optic nerve. Angioid streaks correspond to breaks in the Bruch's membrane, an elastin-rich layer of connective tissue which attaches the retinal epithelium to the lining of the eye. Calcified areas of the Bruch's membrane may break or crack; these breaks correspond to the angioid streaks. The breaks have been described as looking like "sidewalk cracks" or "cracks in porcelain." When blood vessels grow through these breaks and cracks, they may leak or bleed. If these areas of hemorrhage are located in the macula, the area of the eye where central vision is focused, loss of central vision may result.

Every individual affected by PXE should have an annual examination by an ophthalmologist. It is important that the annual ophthalmologic exam be diligent and complete. The eye must be dilated so that the ophthalmologist can examine for angioid streaks. Before angioid streaks are present, minor changes in the eye, called "peau d'orange", may be apparent during ophthalmologic exams. Younger members of an affected family can be screened for these minor eye changes before angioid streaks appear. A retinal specialist may suggest photographing the retina of affected individuals, for the purposes of documentation and future comparison. Rarely, if the retinal specialist suspects that abnormal blood vessels may be growing underneath the retina or if there is unexplained leakage of fluid or blood under the retina, a fluorescein angiogram may be necessary. If an affected individual is at risk for retinal hemorrhage, an Amsler Grid may be used by the patient to identify new areas of visual distortion. Because new areas of visual distortion could indicate a new area of bleeding, the patient should immediately report these to the ophthalmologist.

Individuals who lose central vision may find a low vision clinic helpful. These clinics may help patients overcome some of the disabling effects of vision loss and can instruct them in the use of magnifying devices and reading aids and in mobility.

Sometimes laser surgery is suggested to seal the small blood vessels by photocoagulation. However, if surgery is in the area of the macula, central vision loss can still occur. There is some controversy about the use of laser surgery for PXE patients. Some report excellent results, while others are not satisfied with the outcome of this surgery.

It has been suggested that people with PXE not engage in activities which might cause direct eye injury, including football, boxing, heavy weight-lifting or deep sea diving. However, good aerobic exercise is recommended.

Once PXE is diagnosed, the affected individual should consider all the ramifications of this disease. A detailed history should be taken by the dermatologist and the patient should obtain a referral to an ophthalmologist and a cardiologist. PXE can cause difficulties in the eyes, cardiac, vascular and gastrointestinal systems. There may be special issues for women and pediatric patients.